I chose to use a raft to print on, but it should print fine without it.

You will only need one of the files; they're all the same, I just uploaded different versions so people wouldn't have to guess what size it is going to be when it prints.

V1 and V2: These have the pupil of the model sticking outwards in the eye, giving a physical form for the iris.

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UPDATE:

v3: I've redone the model to make it more accurate to the original designs shape (eye size, teeth.)
I also reversed the "pupil" on the model to try to make the "Follow-Me-Eyes" effect work better. (This was my first try at it.) The bonus to this is that if you want to drill out the eye holes and put in LED's to make them glow it'll be easier! :D

The one inch button size is perfect for giving away; it took my printer about thirty minutes to print it.
The two inch took an hour and twenty minutes to print.

(Infill: 15%. Layer Height 0.27mm, 1 shell, feed rate 20mm/s.)